The present invention relates generally to fluid flow rate selectors, and more particularly, to a fluid flow rate selector using internal seals located on a flat surface instead of on a cylindrical surface to form an axial flow path.
A fluid flow rate selector is used to select a fluid flow rate. A conventional fluid flow rate selector is marketed by Ottico Meccanica Italiana SpA under part number VP256 as depicted in FIG. 1 as reference number 100.
As depicted in FIG. 1, a flow rate selector knob 110 is rotated to select either a low or a high flow rate. The flow rate selector 100 has a fluid inlet 105 which can be attached to a source of pressure (not shown) using an NPT (National Pipe Thread) fitting (not shown). An outlet having a bayonet fitting 120 is connectable to a bayonet coupling 200. As explained below, when the bayonet coupling 200 is fully mated to the bayonet fitting 120, and the inlet is connected to the source of pressure, fluid or gas will flow through the fluid flow rate selector at the flow rate at the selected flow rate. The fluid flow rate selector 100 has a stationary cylindrical body 150 and the knob 110 is rotated relative thereto to select the desired flow rate. A cover 130 is pivoted relative to the knob 110 to expose the bayonet fitting 120.
As depicted in FIG. 2, the bayonet coupling 200 has a central fitting portion 205 having a pair of ramps 210 for engagement with the bayonet fitting 120 and a forwardly extending portion 220. A hose 230 connects the central fitting portion 205 to a user.
Refer now to FIG. 3 which is a cross-sectional view of the fluid rate flow selector 100 of FIG. 1. Positioned within the cylindrical body 150 is a poppet assembly portion 305, connected to the bayonet fitting 120 opposite the inlet 105. The central poppet assembly 305 is biased in a direction towards the bayonet fitting 120. The flow rate selector knob 110 includes a spring loaded ball assembly 320 which is biased radially inwardly to form a seal as explained below. The poppet body assembly 305 includes two or more orifices which extend radially outwardly from a chamber within which the poppet assembly 305 is located. The ball assembly 320 is brought into an engagement with an O-ring 340 which is mounted on an outer cylindrical surface of the poppet body assembly 305. As depicted in FIGS. 1 and 3, the fluid flow rate selector 100 has a high and a low flow rate. Thus, the flow rate selector knob 110 can be rotated to one of two positions in which the orifice 330 is not sealed and the other orifice 310 is sealed. The forwardly extending portion 220 of the bayonet coupling 200 is brought into engagement with the poppet 350 of the poppet assembly 305 causing the poppet to unseat so that fluid can flow around the poppet through the orifice and past the poppet 305.
Disadvantageously, in the fluid flow rate selector of FIGS. 1 and 3 flow rate selector, the sealing O-rings 340 are mounted on a cylindrical surface of the knob 110. The natural shape of the O-rings 340 is planer or flat and in order to be shaped or to conform to the outer cylindrical surface, have to be deformed. Because the O-rings 340 have to be deformed, and attempt to return to their original shape, the O-rings need to be fixed to the outer cylindrical surface using adhesive. Even using the adhesive, there are significant sealing problems associated with the prior art arrangement.
It is, therefore, an object of the present invention to provide a fluid flow rate configured such that moving internal seals are kept in their natural planar shape.
These and other objects of the present invention are provided by a fluid flow rate selector utilizing an inlet mounted on a retaining piece having at least two flow orifices of differing cross-sectional areas such that each flow orifice is capable of limiting fluid flow to a different rate. The flow orifices are formed in a flat planar surface of the retaining piece. On the retaining piece, a flow rate selector body is mounted such that it is free to rotate relative to the retaining piece. A set of seals is mounted on the flat surface of the rotatable flow rate selector body. The flow rate selector body is rotated to align the seals to block the flow orifices, thereby selecting a desired flow rate.
These and other objects of the present invention are achieved by a flow rate selector having a high flow position and a low flow position. The flow rate selector has a flow selector knob having a web. The web has a flat surface. At least two seals are mounted on the flat surface of the web. A retaining piece has two orifices of differing cross-sectional areas. The flow selector knob is rotatable relative to the retaining piece such that at least one seal can be aligned with either of the orifices to prevent fluid flow there through while allowing fluid flow through the other orifice.
The foregoing and other objects of the present invention are achieved by a flow rate selector having a high flow position and a low flow position. The flow rate selector has a flow selector knob having a web. The web has a flat surface. A seal is mounted on the flat surface of the web. A force balancing element is mounted on the flat surface of the web. A retaining piece has two orifices of differing cross-sectional areas. The flow selector knob is rotatable relative to the retaining piece such that the seal can be aligned with either of the orifices to prevent fluid flow there through while allowing fluid flow through the other orifice.
The foregoing and other objects of the present invention are achieved by a flow rate selector having a high flow position and a low flow position. The flow selector knob has a web. The web has a flat surface. A seal is mounted on the flat surface of the web. A force balancing element is mounted on the flat surface of the web. An outer shell has two orifices of differing cross-sectional areas located an equal distance from a center of the outer shell. The outer shell also has a cylindrical extension enclosing part of the flow selector knob. The flow selector knob is rotatable relative to the outer shell such that the seal can be aligned with either of the orifices to prevent fluid flow there through while allowing fluid flow through the other orifice.
Still other objects and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein the preferred embodiments of the invention are shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments and its several details are capable of modifications in various obvious respects, all without departing from the invention. Accordingly, the drawings and description thereof are to be regarded as illustrative in nature, and not as restrictive.